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1

Real-time optical demultiplexing with the chirped pulses

Li Y., Zhang X., Yuan J., Kang Z., Sang X., Kang S., Kang X., Yan B., Wang K., Yu C.

Optica Applicata

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2018

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Vol. 48, nr 4

621--632

EN

A scheme for real-time optical demultiplexing is proposed by utilizing the time-broadened and linearly chirped pulses instead of the conventional mode-locked pulses. The copies of the optical-time-division-multiplexed signal are acquired through a dual-pump parametric gate and used as the parametric multicast block. Simulation results show that the demultiplexing from 160 Gb/s down to sixteen 10 Gb/s tributaries can be achieved only by using a sampling source of 10 GHz. The proposed scheme can effectively reduce the complexity of parallel processing, and find important applications in the high-speed all-optical signal processing.

2

Experimental study on bridge–track system temperature actions for Chinese high-speed railway

Lou P., Zhu J., Dai G., Yan B.

Archives of Civil and Mechanical Engineering

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2018

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Vol. 18, no. 2

451--464

EN

Atmospheric temperature and directed solar radiation have a significant effect on the temperature field of high-speed railway (HSR) concrete bridge and ballastless track structure. However, temperature actions are random process of which distribution laws are difficult to explore, and existing statistical methods for structure temperature analysis are still not precise. So far, there are few researches for annual temperature spectra and design codes for bridge–track system. Based on the one-year observation data, this paper investigated the temperature actions for Chinese HSR bridge–track structure. By utilizing reliability high moment theory, a statistical method which could built virtual distribution was put forward. Based on the renewed study, the effects of waterproof for deck were taken into consideration, a temperature action model was proposed which is suitable for both bridge and track structure. In addition, for track structure, the previous temperature load models were modified. Apart from that, by proposing the concepts of temperature uniform and fluctuant spectra, the research evaluated service performance of structure. Finally, the distribution regularities of uniform temperature spectra were fitted by Fourier series, and the relationship between structural and atmospheric uniform temperature was established (formula (25)). As a result, according to 50 years recorded atmospheric temperature data, the prediction model of the structure extreme temperature was suggested, and by taking the recurrence interval of 100, 150 and 300 years, the extreme temperatures of the system are 52.23, 54.34 and 57.77 °C.

3

Prediction of the Distribution of Alpine Tree Species Under Climate Change Scenarios: Larix chinensis in Taibai Mountain (China)

Zhao X., Meng H., Wang W., Yan B.

Polish Journal of Ecology

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2016

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Vol. 64, nr 2

200--212

EN

Larix chinensis, an endangered and endemic alpine tree, occurs on Mt. Taibai in the Qinling Mountains, China. The extreme sensitivity of this species to climate change makes predicting its future distribution important. Using high-resolution remote-sensing imagery, and the Maxent model, we analysed the current distribution and forecast future distribution of L. chinensis under two climate change scenarios, IPCC A2 and IPCC B2. The results showed that three dominant climatic factors influenced the geographic distribution of L. chinensis: mean annual temperature, mean temperature of the coldest quarter, and precipitation of wettest month. Currently, L. chinensis mainly concentrated at 3100 m and covers an area of 53.52 km2. The population on the southern slope covers approximately twice the area of that on the northern slope; the model simulations indicated that the area of suitable habitat would decrease continually under two climate change scenarios, A2 and B2; the decrease was more obvious in scenario A2, and the range in scenario A2 covers approximately twice the area of that in scenario B2. Under both scenarios, L. chinensis would first be extirpated at lower elevations, and the suitable habitat of this species would move to higher elevations in the Taibai Mountains.

4

EL and ITG Characterization of Large Areas Black Silicon Solar Cells VIA Screen Painting

Tang Y., Zhou C., Wang W., Zhou S., Zhao Y., Liu X., Zhao L., Li H., Chen J., Yan B., Fei J., Cao H., Wu X.

Przegląd Elektrotechniczny

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2013

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R. 89, nr 1b

151--154

EN

A simple process of texturing silicon (Si) surfaces using gold (Au)-catalyzed wet chemical etching was used to form black Si (BS) on a (100) p-type substrate. The surface became uniformly black after 6 min, with a resulting reflectivity of < 2% over the 400 nm to 1100 nm wavelength range. Large areas (153.18 cm 2) of black Si solar cells (BSSCs) with an n + -p-p + structure were also fabricated using conventional processes, including POCl3 diffusion, screen printing, and co-firing. The resulting cells were divided into two groups according to the emitter (46 and 37 Ω/), and their output parameters were studied. The best convention efficiency (Eff) was < 10%. The open-circuit voltage (Voc) was particularly low because of poor surface passivation, and the shunt resistance (Rsh) linearly decreased with the series resistance (Rs). Electroluminescence (EL) and infrared thermography (ITG) measurements were conducted to characterize the BSSCs. Both the emissivity and temperature were low and nonuniform. Optimizing the fabrication process by reducing the etching depth and lowering the dopant sheet resistance led to significant improvement in Voc (~48 mV) and Eff (~3.8% absolute). EL and ITG measurements indicate that Rs is another important factor that accounts for the poor properties of the BSSCs.

PL

Do wytworzenia czarnego krzemu (BS) na podłożu typu p-Si(100) zastosowano prosty sposób teksturowania powierzchni krzemowej metodą chemicznej akwaforty na mokro z zastosowaniem, jako katalizatora, nanocząstek złota (Au). Podłoże staje się jednolicie czarne po 6 min, osiągając współczynnik odbicia < 2% w zakresie długości fali od 400 nm do 1100 nm. Wykonano również dużą powierzchnię czarnych krzemowych ogniw słonecznych (BSSC), ze strukturą n + - p -n +, konwencjonalnymi metodami obejmującymi dyfuzję POC13,drukowanie maski i wyżarzanie. Otrzymane ogniwa dzielą się na dwie grupy w zależności od emitera (46 i 37Ω/): zbadano ich wyjściowe parametry. Najlepsza uzyskana wydajność wynosi < 10%. Napięcie obwodu otwartego (Voc) jest szczególnie niskie z powodu słabej pasywacji powierzchni, a rezystancja równoległa (Rsh) liniowo maleje z rezystancją szeregową (Rs). Charakterystykę BSSC określają pomiary elektroluminescencji (EL) i tomografii w podczerwieni (ITG).Zarówno emisyjność jak i temperatura są niskie i niejednorodne. Optymalizacja procesu wykonana przez zmniejszenie głębokości akwaforty i obniżenie rezystancji warstwy domieszkowania prowadzi do znaczącej poprawy Voc (ok. 48mV) i Eff (ok. 3,8%).

5

Luminescent homo- and hetero-metallic hybrid molecular materials constructed by covalent grafting

Wang F. F., Yan B.

Materials Science Poland

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2013

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Vol. 31, No. 1

108-114

EN

In this paper, 3-(triethoxysilyl)-propyl isocyanate (abbreviated as TESPIC) was modified by ethylparaben (EPB) to produce corresponding organic-inorganic monomers (EPB-TESPIC) with two components equipped with covalent bonds, which not only can coordinate to RE ions (Tb3+ and Eu3+) but also act as a sol-gel precursor. Luminescent hybrid materials consisting of terbium-europium complex, covalently bonded to silica-based network, have been obtained in situ via a sol-gel approach. Proton nuclear magnetic resonance spectroscopy (1HNMR) and Fourier transform infrared spectroscopy (FT-IR) were applied to characterize the structure of EPB-TESPIC. UV-visible, phosphorescence, and luminescence spectra were obtained to characterize the photophysical properties of the obtained hybrid material. Through co-hydrolysis and polycondensation, Tb3+ and Eu3+ can be introduced into the same organic-inorganic hybrid monomer, forming Si-O backbones. The experimental results show that the strong luminescence of rare-earth ions substantiates the optimum energy match and effective intramolecular energy transfer between the triplet state energy of coordination complex and the emissive energy level of the rare-earth ions. The hybrid material systems are expected to have potential applications in photophysical sensors.

6

Using sustainable competitive advantages to measure technological opportunities

Takala J., Muhos M., Tilabi S., Tas M. S., Yan B.

Management and Production Engineering Review

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2013

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Vol. 4, No. 3

55--64

EN

The goal of this paper is to help small and medium size enterprises (SMEs) to find operative competitive advantage. This paper introduces a new method which applies critical factor analysis, risk and opportunities analysis to measure and propose resource allocation for companies in couple of next years. this research shows Knowledge/Technology (K/T) Calculation effect on (Balanced) Critical Factor Index (CFIs) depending on the proportions allocated among the different technological levels (Basic, Core or Spearhead) for each attribute separately. Moreover it helps firms to take balance in resource allocation for each attribute in changing environments on the basis of different level of technology. This paper presents the ’first in the world’ case study on operative sustainable competitive advantage and corresponding risk levels by taking into account technology and knowledge effects for 7 SME companies.

7

Photofunctional terbium centered inorganic/organic hybrid material with the functionalized 5-dihydroxybenzoate linkage

Li Y., Sui Y. L., Yan B.

Materials Science Poland

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2012

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Vol. 30, No. 1

39--44

EN

In this study, silica-based organic-inorganic hybrids were prepared using sol-gel methods. A new kind of monomer (DHBA-TESPI) was derived by modifying the double hydroxyl groups of 3, 5-dihydroxybenzoic acid (DHBA) with 3-(triethoxysilyl)-propyl isocyanate (TESPI) through the addition reaction. Then, the obtained compound and tetraethoxysilane (TEOS) were used as the inorganic and organic counterparts respectively. Coordination reaction between Tb3+ and the carboxylic groups of the monomer happen simultaneously. IR, NMR, UV/Vis absorption, low-temperature phosphorescence spectroscopy and fluorescence spectroscopy were used to characterize the hybrids. The final materials exhibited strong green-colored fluorescence (Tb3+), which can be explained by the intramolecular energy transfer caused by coordination of the organic counterpart. The spectroscopic data also revealed that the triplet state energy of the organic ligand matches the emissive energy level of Tb3+.

8

A Novel Tetranuclear Iron Complex [Fe4O2(O2CC2H5)7(bipy)2]PF6.2H2O (bipy=2,2'-Bipyridine):Synthesis, Crystal Structure and Magnetic Properties

Yan B., Chen Z. D.

Polish Journal of Chemistry

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2001

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Vol. 75, nr 6

785-793

EN

A novel tetranuclear iron-oxo complex has been synthesized and characterized by X-ray single crystal structural analysis: [Fe4O2(O2CC2H5)7(bipy)2]PF6_2H2O (bipy = 2,2_- bipyridine). The title complex crystallizes in the monoclinic system, space group C2/c, with lattice parameters a = 27.859(2) A, b = 13.0629(10) A, c = 17.2698(14) A, _ = 123.6080(10)_, V = 5234.3 (7) A3, Dc = 1.559 Mg/m3, Z = 4, R1 = 0.0493. The molecular structure shows that there are two types of coordination environment for Fe(III) atoms. One is formed by two N atoms and four O atoms, another by six O atoms, all in distorted octahedron, which forms a "butterfly" core structure. The corresponding variable temperature susceptibility measurement shows the antiferromagnetic interactions in the complex.